<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
    <style>
        p {
            color: red;
            font-size: 12px;
        }

        h3 {
            color: rgb(21, 110, 188);
            font-size: large;
        }

        h4 {
            color: rgb(233, 143, 25);
            font-size: medium;
        }
    </style>
</head>

<body>
    <p>变成红色</p>
    <h3>nansheng</h3>
    <h3>nansheng</h3>
    <h3>nansheng</h3>
    <h4>nvsheng</h4>
    <h4>nvsheng</h4>
    <h4>nvsheng</h4>
    <h4>nvsheng</h4>
</body>

</html>